ICD-10 Code G52.0 – Disorders of olfactory nerve (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G52.0 – Disorders of olfactory nerve
What it is
G52.0 identifies a disorder of the olfactory nerve, which carries smell signals from the nose to the brain. Use it when documentation shows impaired smell related to this cranial nerve.
Clinical signs
Common findings include reduced smell, loss of smell, or abnormal smell perception. Clinical features vary; refer to documentation and confirm that the olfactory nerve is the documented source.
When to use this code
Use G52.0 when the provider documents an olfactory nerve disorder, such as anosmia or other smell dysfunction attributed to that nerve. It also fits when the note clearly links the patient’s complaint to cranial nerve I involvement. If the record only says “smell loss” without a nerve diagnosis, check documentation.
Do not use for
Do not use this code for general nasal congestion, sinus disease, or smell changes from non-neurologic causes unless the olfactory nerve disorder is documented. Do not assume the code from symptoms alone.
Coding tip
Code G52.0 only when the chart supports a cranial nerve diagnosis, not just a complaint of altered smell.